A set-top terminal (STT) serves as a gateway between a user's television and the cable feed carrying incoming signals. An STT receives, from a cable network, encoded signals containing programming content, decodes the signals, and converts them into analog signals displayable by the television. The STT also accepts commands from the user relating to the user's choices for programming and services.
Typically, an STT includes an operating system and one or more resident applications (RAs) stored in memory. An RA may comprise one or more software routines, and provides functionality to the STT when the RA is executed. For example, an RA may provide a parental-blocking function that enables a user to block the viewing of selected programs or channels based on one or more factors including rating, channel, or time. Other functions that may be incorporated in an RA include an interactive program guide (IPG) that displays television program information, including program name, start time and duration, and a navigator that can be used to select services and applications offered over the cable network.
Many RAs record various aspects of the STT user's behavior. For example, a parental-blocking application may record data indicating which programs or channels the user wishes to have blocked. An RA may also record a user's program choices and keep track of the user's favorite programs or channels. Data relating to user choices and preferences (such data being referred to as “user parameters”) are stored in memory in the STT so that the RA may access the data and optimize its functionality to the user.
In many cable networks, the cable operator periodically updates the RA that resides in one or more STTs to improve the STT's functionality or to provide new services. This is ordinarily accomplished by broadcasting an updated version of the RA over the network from the cable operator's headend facility to one or more STTs. The STTs receive the updated RA and download it into memory. The updated RA is typically a modified version of the original RA stored in the STTs. Additionally, because software errors and other problems are sometimes discovered in the process of introducing an updated RA, it is sometimes preferable to conduct a trial of the updated RA on a limited number of STTs in the network before installing it on all STTs.
Many cable operators avoid replacing an existing RA with an entirely new RA, because this process can result in a loss of the user parameters that are stored in the STT memory. Typically, when a respective RA generates and stores user parameters in the STT memory, the user parameters are formatted and organized in a manner specific to the respective RA, and cannot be read or interpreted by a different RA. As a consequence, the process of installing a new RA can result in the new RA being unable to read or interpret correctly the user parameters that are stored in the STT memory. In such a case, installing the new RA may result in the loss of information such as, for example, parental blocking choices, in which case any program may become viewable on the user's television from the moment the new RA is downloaded and executes. In many cases, the only solution is for the user to re-enter his or her choices and preferences in accordance with the new RA's user interface. Such a loss of user preferences is unacceptable to many users (and to many cable operators).